XVIII.] 



ELM. 



155 



This precaution is considered necessary, owing to the 

 great liability of the planks to warp or twist, which would 

 soon render them unfit, for use. 



As Elm timber is best and most durable when worked 

 up soon after the tree is felled, it is not necessary to keep 

 in store more than is required from year to year. If, 

 however, it should be thought desirable to accumulate 

 stock with the view to provide against emergencies, it 

 will be most effectually preserved for future use by 

 keeping it constantly under water, or burying it in mud. 



Table XLI., showing the transverse strength of this 

 wood, is not so full or satisfactory as could be desired, 

 owing to the difficulty experienced in finding pieces 

 sufficiently straight in the grain for experimental pur- 

 poses. The Tables XLII. and XLIIL, showing the 

 tensile and vertical strength, are, however, more reliable. 



Table XLI.— Elm (English). 

 Transverse Experime?its. 



